The government will today come under pressure to disclose all it knows about how Benyam Mohammed, a British resident held in Guantánamo Bay, was seized in Pakistan in 2002, and the likelihood that he would be tortured when he was moved to American custody.

Mr Mohammed, 27, is accused of planning al-Qaida attacks. Following his arrest in Pakistan he was flown on a CIA rendition flight to Morocco, where he was allegedly tortured. The Council of Europe highlighted his case in a report this month in which the UK is accused not only of allowing the use of British airspace and airports, but of providing information used during his torture. Today, the all-party group on extraordinary rendition will hear there is strong prima facie evidence of British involvement in Mr Mohammed's seizure in Pakistan in 2002 and his subsequent secret transportation to Morocco and Afghanistan before been flown to the US camp in Cuba.

The former foreign secretary Jack Straw, told the Commons foreign affairs committee last year that while in jail in Karachi, Mr Mohammed was interviewed by a member of MI5. Mr Straw said MI5 had no role in his capture or in his transfer from Pakistan. He denied that the officer had noticed any evidence of torture, and said Mr Mohammed had not complained of ill-treatment. However, MPs say the Foreign Office has refused to cooperate with their requests for further information, according to Andrew Tyrie, Tory chairman of the group.

In his report for the Council of Europe this month the Swiss senator Dick Marty said Britain could be held responsible to a degree for the violation of Mr Mohammed's rights and was obliged to investigate his allegations of torture. He reported that Mr Mohammed was flown from Morocco to Afghanistan on a CIA charter aircraft.

Clive Stafford Smith, Mr Mohammed's lawyer, said: "My client is in Guantánamo Bay. He was born in Ethiopia but he lived in England, where he appreciated the sanctuary given to him from his own brutal government. The British government is beginning to look no less brutal."

Mr Tyrie said: "The Council of Europe has called on the UK to look into the rendition and apparent torture of Benyam Mohammed. Instead of agreeing to do so, the prime minister simply asserted that the report said nothing new."

Mr Mohammed, 27, who grew up in Notting Hill, west London, was arrested at Karachi airport, allegedly for trying to travel on a false passport. He was transferred into US custody. While in Morocco, he says, he endured torture and confessed to being part of a "dirty bomb plot". He says he made complaints of ill-treatment to two British officers who interviewed him in Karachi, where he was whipped and beaten, and the ill-treatment then stopped.

In January 2004 Mr Mohammed was "rendered" by the US to the infamous "dark prison" in Afghanistan, where he says he endured torture for five months before he was flown to Guantánamo Bay.

He is expected to be tried this year by a US military commission at the detention camp. He denies the charges against him.